Commutator-slotting apparatus



Oct. 13,1925- J. J. CARTER COIIUTATOR SLOT'IING APPARATUS --Sheet 1 .Illllll-lllll Patented Oct. 13, 1925.

UNITED, STATES PATENT" OFFICE. M

JOHN J. CARTER, or ANDERSON, INDIANA, ASSIGNORTO GENERAL MOTORS CORPORA- TIoN, A CORPORATION or" DELAWARE. v

I CoiiIMtITAToE-SLOTTING APPARATUS.

Application filed October 31, 1923. Serial No. 622,008.

To allwhom it may concern:

Be it known that I, JOHN J. CARTER, a citizen of the United States ofAmerica, residing at Anderson, county of Madison, State of Indiana, have invented certain new and useful Improvements in Commutator- Slott-ing Apparatus, of which the following is a full, clear, and exact description.

This inventlon relates to the manufacture of commutato-rs for dynamo 616013116 machines, and particularly the type of .com-

' the present invention-to reduce the cost of manufacture V of such "commutators, and therefore, the invention consists in providing mechanism for slotting all of the commutator "risers simultaneously.

Other and further objects and advantages of'the present invention will be apparent from the following description, reference being had to the accompanyingdrawings, wherein a preferred embodiment of one form of the present invention, 'is clearly shown. r

p In the drawings: V k

Fig. 1 is a plan view of the commutator fixture included in the'present invention.

Fig. 2 is a sectional view on the.line,22 of Fig. 1.

Figs. Sand 4 are side and end views, respectively, of one of the spacing blocks included in the apparatus shown in Fig. 1.

Fig. 5 is a longitudinalsectionalview of the apparatus showing one form of the invention, and

Fig. 6 is a plan View of a part for retaining in position the tools for cuttingthe slots in the risers. V J r 7 In the drawings, 20 designates a plunger mounted preferably for vertical movement which .isefiected by means of a crank 21, crankshaft 22, a pinion 23 attached to crank shaft 22 and meshing With a rack 24 attached to the plunger 20. Plunger 20 is provided with a central recess 25 for receiv ing the shank 26 of a plate 27. A set screw 28 retains the shank 26 in position. To the plate 27 is secured by means of screws 29 and dowel pin 30,21. retaining block 31 which includes a; centrally. disposed hub portion 32 from which radiate a plurality of wedgeshaped portions 33 spaced by radially extending notches 34. The block 31 is pro-' vided also with an annular groove 35 which intercepts each of the notches 34. Each notch-34 receives a broaching ba1136 having a back edge 37 parallel to th line-of motion of the'plunger 20, a plurality of broaching' teeth 38 progressively .varying in distance from the back. edge 37, and a'beveled lower edge surface 39. The portion of each blade 36 which is included between the surface 39 and'the teeth 38 is also. beveled as indicated at 40. As viewed in Fig. 5, the difference between the horizontal distance from the highest cuttingtooth to the back edge 37 and the horizontal distance between the lowest cutting tooth 38 and the back edge 37 will be equal to th depth commutator riser. y

The top edge 41 of bar 36 abuts the lower of slot cut in the surface of plate 27." Each bar 36 is pro--- vided with a tang 42 which is received by the annulargroove35. Each notch 34 of block 31 receives one of the broaching bars 36, there being as many bars as there are commutator risers to be slotted. The bars 36 are retained in position by set screws 43 carried by a retaining ring 44. To provide clearance for the end of set screws 43, the retaining block 31 is provided with a plurality of'reccsses 45 located adjacent each notch 34..

The bars 36 are identical except for one, namely, bar 36 which is provided with an extension 46 which serves as a pilot and as means for locating the commutator indicated at 50 in Figs. 1 and 5. The commutator 50 may be any having risers extending from the brush engaging portion of the commutator segment, but for purposes of illustration, the commutator described and claimed in the patent to Oliver F. Conklin, Number 1,503,484, issued August 5, 1924,11as been chosen. The commutator 50 includes aplurality of segments 51 clamped together by V-rings 52 and a clamping tube 53having its ends 54 flaredovcr the outer faces of the l-rings. Each segment 51 includes two bars 55 and 56 which when assembled as shown in Fig. 1, provides a riser having a V-noteh 57. In order that th riser may be notched to receive the ends of armature conductors which are rectangular in cross section, it is desirable that the metal in the riser be cut away to change the V-notch to a rectangular notch.

The fixture which holds the commutator 50 while being operated upon and which guides the breaching bars 36 and 362 comprises a block 60 adapted to be secured preferably upon a horizontal support. The block 60 is provided with an aperture 61 in alinement with the block 31. From the aperture 61 there radiates a plurality of notches 62 located in alinement respectively with the several broaching blades 36. The block 60 is provided with a recess concentric with the aperture 61. This recess includes an annular groove 63, and receives a plurality of guide blocks 64 which are spaced by blocks 65, each block having a tang 66 received by the annular groove 63. The blocks are located in radial alinem-ent with the notches 62, and the blocks 64 are located by dowelpins 67 and are secured by screws 68. The side edges of that portion, of the upper surface of each block 64 which extends between notches 62 is chamfered as indicated at 69 in Figs. 1, 3, and 4. The blocks 65 are as thick as the width of the notches 62. Since these blocks are in radial alinement with notches 62, each block 64 will include a portion which is in verticalalinement with a portion 70 of the block 60 which is in eluded between adjacent notches 62. There are as many blocks 64 as there are bars 36. Therefore, there will be a space between adjacent blocks 64 for receiving each broaching bar. In this manner, the broaching bars are guided through the work.

Preferably, the uppermost position of the plunger 20 is such that. the extension 46 of bar 36 will still project between two of the blocks 64 as shown in Fig. 5. A commuta tor to be slotted is located upon the fixture as shown in Figs. 5 and 1, with its main or brush engaging portion disposed between the ends of the blocks 64 and its riser portions resting upon said blocks 64. One of the notches 57 is disposed so as to be received by the extension 46. Consequently, the other V-notches 57 will be located in alinement with the notches 62 and spaces between the blocks 64.

The means for preventing endwise movement of the commutator in one direction includes two clamping devices, each comprising a slidable bar having a clamping end 81 which is notched to receive one of the broaching bars 36. The bar 80 is slidable along a grooved block 82 secured to the base block 60 by screws 83. A. stud 84 threaded tightly into the block 60 extends through a hole 85 in block 82, a coil spring 86, a washer 87 and an elongated hole 88 in block 80. Thethreaded' upper end 89 of stud 841eceives a nut 90. The movement of nut 90 is limited by a pin 91 attached to the bar 80 and projecting into an arcuate groove 92 in the nut 90. The groove 92 is intercepted by a radially extending groove 93 connecting groove 92 with the threaded aperture in nut 90. When the bar 80 is in the position shown in the drawings and the nut 90 is turned clockwise as viewed in Fig. 1, portion 81 of the bar 80 will be clamped against the commutator. When the nut 90 is turned counter clockwise, the clamping bar 80 will be released and the spring 86 will cause the portion 81 to be separated from the commutator. The formation of the groove 93 provides a camming surface 94 which will engage the pin 91 when the nut 90 is turned counter clockwise and cause the bar SOto be withdrawn from the commutator so that the commutator may be removed from the fixture. Obviously turning the nut clockwise will cause the bar 80 to move toward the commutator into the position shown in Fig. 5, and further turning of the nut clockwise will cause the bar 80 to be clamped against the commutator.

Turning the crank 21 counter clockwise as viewed in Fig. 5, will cause the plunger 20 to descend and force the broaching bars into the V-notches 57 of the commutator risers. Bars 36 are guided by the blocks 64 so that lateral movement is prevented. The result is that the broaching bars which cut away the material of the risers adjacent the notch 57 provide a notch of rectangular shape. Turning the crank 21 clockwise causes the bars 36 to be withdrawn from the fixture so that the commutator may be removed after the clamping bars 80 have been withdrawn sidewise.

The mechanism disclosed for operating the plunger 20 is only illustrative, and it is to be understood that any suitable powerdriven mechanism may be employed if desired.

It is to be understood also, that the mechanismillustrated is applicable to commutators other than that shown in the drawings. The broaching bars are capable of cutting slots in commutator risers which are not provided with slots previous to the slotting operation.

While the form of embodiment of the in vention as herein disclosed, constitutes a preferred form, it is to be understood that other forms might be adopted, all coming within the scope of the claims which follow:

\Vhat is claimed is as follows:

1. Commutator slotting apparatus comprising incombination, a plurality of tools each adopted to slot 2. commutator segment,

a tool holder adapted to be connected with said tools and maintain them in spaced re lation, a work holder including a clamping member having a portion movable laterally toward the commutator and movable longitudinally thereof to clamp the commutator in position, and a common operating member for moving said clamping member in both directions.

2. Commutator slotting apparatus comprising in combination, a plurality of tools, each adapted to slot a commutator segment, a tool holder adapted to be connected with said tools and maintain them in spaced relation, a work holder for maintaining said commutator in position, said Work holder including a clamp having a portion movable laterally and. longitudinally with respect to the commutator, and a rotatable screwthreaded member for causing said clamp to move longitudinally to clamp the commu tator, said screw-threaded member and clamp having cooperating provisions whereby partial rotation of said member will cause said clamp to move longitudinally With respect to the commutator and further rotation causes the clamp to move laterally with respect to the commutator.

In testimony whereof I hereto afiix my signature.

JOHN J. CARTER. 

